Largely enhanced thermal and mechanical properties of polymer nanocomposites via incorporating C60@ graphene nanocarbon hybrid

Although considerable progress has been achieved to create advanced polymer nanocomposites using nanocarbons including fullerene (C-60) and graphene, it remains a major challenge to effectively disperse them in a polymer matrix and to fully exert their extraordinary properties. Here we report a novel approach to fabricate the C-60@graphene nanocarbon hybrid (C-60: similar to 47.9 wt%, graphene: similar to 35.1%) via three-step reactions. The presence of C-60 on a graphene sheet surface can effectively prevent the aggregation of the latter which in turn helps the dispersion of the former in a polymer matrix during melt-processing. C-60@graphene is found to be uniformly dispersed in a polypropylene (PP) matrix. Compared with pristine C-60 or graphene, C-60@graphene further improves the thermal stability and mechanical properties of PP. The incorporation of 2.0 wt% C-60@graphene (relative to PP) can remarkably increase the initial degradation temperature by around 59 degrees C and simultaneously enhance the tensile strength and Young's modulus by 67% and 76%, respectively, all of which are higher than those of corresponding PP/C-60 (graphene) nanocomposites. These significant performance improvements are mainly due to the free-radical-trapping effect of C-60, and the thermal barrier and reinforcing effects of graphene nanosheets as well as the effective stress load transfer. This work provides a new methodology to design multifunctional nanohybrids for creating advanced materials.